Phenols aquatic plants

Rhizodegradation Soils, sediments, land application of wastewater Organic compounds (TPH, PAHs, BTEX, pesticides, chlorinated solvents, PCBs) Phenolics releasers (mulberry, apple, osage orange) Grasses with fibrous roots (rye, fescue, Bermuda) for contaminants 0-3 ft deep Phreatophyte trees for 0-10 ft Aquatic plants for sediments... 

Studies on phytotoxicity of bibenzyl derivatives were extended to duckweed axenic cultures. Bibenzyls 19 and 20 as well as the synthetic analogs 23—28 were tested by triplicate in cultures of the small aquatic plant. Analogs 23—28 were synthesized to investigate the effect on phytotoxicity of oxygenated substituents (phenolic vs. phenolic methyl ether) and their location on the bibenzyl core structure. All synthesized analogs but... 

Pentachlorophenol is metabolized by the aquatic plant Eichhornia crassipes to a number of metabolites including di-, tri-, and tetra-chlorocatechol, 2,3,5-tri- and tetrachlorohydroquinone, pentachlo-roanisole, and tetrachloroveratrole (Roy and Hanninen 1994). The phenolic compounds should be compared with those produced during the photochemical (see Figure 4.4) and the initial stages in the microbiological metabolism of pentachlorophenol (Chapter 6, Section 6.5.1.2), followed by O-methylation (Section 6.11.4). 

In parallel the chemical analysis of the water from the sites of C. demersum growth was made to ensure the proper interpretation of the element composition and IR spectra of the aquatic plants from industrial regions. Chemical analysis was performed with the aid of a spectrofluorimeter Fluorat-02-Panorama and capillar electrophoresis system Kapel-105 (Lumex). Determination of the contents of inorganic anions, surfactants, petroleum products, and phenols in water was made in accordance with standard methods described in [11-14]. 

Uptake of most phenols by aquatic plants is initially rapid, followed by attainment of a steady state in residues. This may occur within 10-20 minutes of initial treatment, depending on compound, species, and exposure concentration (Figure 8.6). Uptake rate probably increases with temperature in most species but is inversely related to pH. Although data are not available for most compounds, Virtanen and Hattula (1982) reported concentration factors of 200-4500 for three species of algae exposed to 2,4,6-trichlorophenol for 21-36 days. 

Other aquatic weeds such as reed mat, mangrove (leaves), and water lily (Nymphaceae family plants) have been found to be promising biosorbents for chromium removal. The highest Cr(III) adsorption capacity was exhibited by reed mat (7.18 mg/g), whereas for Cr(VI), mangrove leaves showed maximum removal capacity (8.87 mg/g) followed by water lily (8.44 mg/g). It is interesting to mention that Cr(VI) was reduced to Cr(III), with the help of tannin, phenolic compounds, and other functional groups on the biosorbent, and subsequently adsorbed. Unlike the results discussed previously for the use of acidic treatments, in this case, such treatments significantly increased the Cr(VI) removal capacity of the biosorbents, whereas the alkali treatment reduced it.118... 

NOM is common in sediments, soils, and near ambient (<50 °C) water. The materials result from the partial decomposition of organisms. They contain a wide variety of organic compounds, including carboxylic acids, carbohydrates, phenols, amino acids, and humic substances (Drever, 1997, 107-119 Wang and Mulligan, 2006, 202). Humic substances are especially important in interacting with arsenic. They result from the partial microbial decomposition of aquatic and terrestrial plants. The major components of humic substances are humin, humic acids, and fulvic acids. By definition, humin is insoluble in water. While fulvic acids are water-soluble under all pH conditions, humic acids are only soluble in water at pH >2 (Drever, 1997, 113-114). 

Other plants such as potatoes, cauliflower, cherries, and soybeans and several fungi may also be used as sources of peroxidase enzymes. Soybeans, in particular, may represent a valuable source of peroxidase because the enzyme is found in the seed coat, which is a waste product from soybean-based industries [90]. In this case, it may be possible to use the solid waste from the soybean industry to treat the wastewaters of various chemical industries. In fact, the direct use of raw soybean hulls to accomplish the removal of phenol and 2-chlorophenol has been demonstrated [105]. However, it should be noted that this type of approach would result in an increase in the amount of solid residues that must be disposed following treatment. Peroxidases extracted from tomato and water hyacinth plants were also used to polymerize phenolic substrates [106], Actual plant roots were also used for in vivo experiments of pollutant removal. The peroxidases studied accomplished good removal of the test substrate guaiacol and the plant roots precipitated the phenolic pollutants at the roots surface. It was suggested that plant roots be used as natural immobilized enzyme systems to remove phenolic compounds from aquatic systems and soils. The direct use of plant material as an enzyme source represents a very interesting alternative to the use of purified enzymes due to its potentially lower cost. However, further studies are needed to confirm the feasibility of such a process. 

Phenol is biodegradable by both aerobic and anaerobic pathways. Little will accumulate in plants or animals and complete aerobic bacterial degradation will produce carbon dioxide. Still phenol is considered a potent insecticide, herbicide, and fungicide. The LC50 for aquatic organisms ranges from 12 to 68 mgl ... 

During the last decade parathion has been the most used organo-phosphorus insecticide. It has been proved to be valuable in crop protection 27). However, using this compound so much has also resulted in numerous accidental intoxications, and many have been lethal 28). In aquatic environments parathion hydrolyzes to yield p-nitro-phenol or oxidizes to yield paraoxon (25, 26). Baker (29) has shown that substituted phenols aflFect the odor quality of drinking water. p-Nitrophenol may be chlorinated at a water treatment plant to produce an odorous product. The U. S. Public Health Service has adopted 1 /xg/liter as a limit for phenolic compounds in water (10). Paraoxon is more toxic to insects and mammals than the parent compound parathion (27). The lethal dose (LD50) for male white rats is 14 mg/kg for parathion while that determined for paraoxon is only 3 mg/kg (30). Bioassay studies with fathead minnows indicated a Median Tolerance Limit (TLni) (96 hours) for parathion of 1.4 mg/liter and 0.3 mg/liter for paraoxon. 

Unfortunately, PCP often contains impurities that are toxic not only to fungi and bacteria but also to other living organisms. Its environmental impact includes effects on human health as well as on plants and other environmental organisms, such as aquatic species and wildlife. Its impurities include the less chlorinated phenols, polychlorinated phenoxy phenols, polychlorinated dibenzo-p-dioxins, and polychlorinated furans. By the late 1980s, pentachloro-phenol and its impurities had become so ubiquitous in the environment that its use has now been restricted. 

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